The Committee on Publication Ethics (COPE) stresses the crucial role of ISSN in its 16 Principles of Transparency
COPE has released a discussion document about predatory publishing (https://publicationethics.org/predatory-publishing-discussion-document) which contains recommendations to help researchers pinpoint fake scientific journals. COPE advises researchers to search the ISSN of the publication in the ISSN Portal and verify if the ISSN is genuine and has not been assigned to another serial publication.